Preparation of protein compositions and masses having improved physical characteristics



Nov. 20, 1945. J. BJORKSTEN 2,389,292

. PREPARATION OF PROTEIN COMPOSITIONS AND MASSES HAVING IMPROVED PHYSICAL CHARACTERISTICS Filed Feb. 8, 1945 v I fiz t arzzegcy Patented Nov. 20, 1945 NlTED STATE PAT Elillforr cg PREPARATION OF PROTEIN COMPOSITIONS I AND MASSES HAVING -mrnovnn PHYSI- oAL CHARACTERISTICS I Johan Biorksten, Chicago, Ill.

v Application February 8, 1945, Serial No. 576,736

18 Claims.

. This invention relates to the preparation of protein compositions and masses having improved physical characteristics,and is a continuation in part of my co-pending application Serial No. 480,586, filed March 25, 1943.

Itis well known that proteins may possess considerable resiliency, and that this resiliency may be further enhanced by the incorporation of plas-' Such plasticized protein masses, how- An object of this invention is to provide pro- I tein compositions having a higher melting point concurrent with retained elasticity, than has been possible heretofore, articles of manufacture comprising such compositions, and methods for preparing them.

of additional glycerol, pre-warmed in the same water-bath.

The resultant mix. was divided in .two 50% aliquots. To one of these I added 60 cc. of 33% acetaldehyde solution, as tanning agent; the other aliquot served as my non-tanned control. The mixes were allowed to stand one-half hour at 55 to eliminate air bubbles, and were then poured to form uniform sheets having the dimensions 330 mm. x 216mm. x 2.5 mm. Two s ili gh sheets were obtained from each aliquot. sheets were allowed to stand for twenty hours at room temperature in order to give them the firmnessrequired.

After this period, one tanned sheet I and one non-tanned sheet 2 were attached with one short end to a rigid metal holder 3, and with .the other short end toa holder 4 having a. reciprocating motion, so that the sheets were continually stretched and relaxed at. a rate of eight times per minute, to an extent of 10% elongation.

The sheets I and2 are clamped in the holders 3'and 4 by means of screws 5, 6, I and 8, The

' reciprocating motion is provided by a disk iil Further objects and morespecific embodiments will become apparent as the following detailed description proceeds.

I have discovered that when a resilient protein composition is rhythmically stretched and relaxed while under the influence of an organic tanning agent, the melting point of the composition will increase about as much as would be thecase if no such stretching took place, but the loss of the tensile strength .will be substantially reduced, frequently entirely eliminated, and in some cases increased, both in' the direction'of the stretch and in directions perpendicular thereto.

This efiect is thoroughly different in kind from the increase in tensile strength in stretching of rayon filaments, which is due to an orientation of molecules in' the direction of stretch. The effecthere disclosed takes place only in the presence of an organic tanning agent, only when stretching is carried out concurrently with an increase in melting point caused by this tanning agent, and the effect takes place in directions "perpendicular to the stretching as well as in the direction of the stretch.

The following example will serve to illustrate this invention, reference being had to the accom-' panying drawing which shows a diagrammatic view of a reciprocating device for stretching and relaxing the sheets:

300 grams of 225 Bloom pig skin gelatin was allowed to swell in a mixture of 300 grams of glycerol and 450 grams of water, at room 'temperature. After one hour, the mixture was melted in a water-bath of 55 and mixed with 1500 grams rotating on shaft II by means not shown. An arm I! is pivoted at [3 and I4 and connected to the holder i by a sliding shaft mounted in support 9, whereby on rotation of the disk in holder 4 reciprocates and thus stretches and relaxes the sheets i and 2.

The other two sheets, one tanned and one nontanned, were placed on a porous backing next to the stretching machine, and were thus exv posed to room temperatures, humidities and ventilation identical with those of the stretched samples.

After twelve days, the stretching was interrupted, the sheets were kept overnight (sixteen hours) at relative humidity and 21. Test strips were cut from center and ends of each sheet having their length parallel to the direction 1 of stretch, and others perpendicular therno, and

the tensile strength was determined in a conventional paper tensile strength testing machine.

The tabulated figures are averages of triplicate determinations, all of which were within 5% of the averages shown. w

. TABLE Tensile strength in grams per sq.' mm.

I Across In dlrectior direction of etch of stretch Stretched tanned sheet, ggg l" Stretch non-tanned sheet End Tanned non stretched sheet. Non-tanned non stretched sheet.

With the stretched sheets, determinations were slight deviations near the edges,

The most striking facts shown by these data are: (-I) that the stretched tanned sheet not 5 only is vastly stronger (320%) than the nonstretched tanned sheet in the direction of stretch, butalso in the direction of perpendicular to the tension (240%);'(1I) that the stretchedtanned sheet is materially stronger in the direction of stretch than is the non-tanned sheet; (111) that in the non-tanned sheets there is no correlation between strength and direction of stretch, while in the tanned sheets this correlation is pronounced; (IV) that in the non-tanned sheets, stretching did not. cause any observable increase in strength,

Since the strength of the stretched tanned sheet was several times greater than that of the non-stretched tanned sheet, it appeared advisable to investigate whether the tanning itself had been impeded by the stretching process.

For this purpose, the softening points of the sheetsweredetermin'ed on circular-samples of mm. diameter,, by the ring and ball method, 25

in oil-bath.

The softening points of both of the non-tanned sheets were 60:1,,whilethose of the stretched as well as the non-stretched tanned sheets exceeded 110 C. i The elongation of the stretched sheets at the termination of the test was approximately 5%,

- polyglycerols, acetamid, toluene sulfonainid, 11.. butyl tartrate, and the like.

. Suitable tanning agents include formaldehyde, acetalclehyde, butyraldehyde, crotonaldehycle, tannic acid, 'parabenzo quinone, hydroquinone, trlethanolamine, organic substances containing a free sulfonic acid group, and generally any organic substance capable of reacting'simultaneousl with any free groups in two diiferen't protein molecules, so 'as to form a bridge between, these protein molecules, Generally, I prefer to employ for the purposes of the invention an aidehyde having less than five carbon atoms, or a quinone derivative having tanning action, although any other of the organic comp unds disclosed may-be used.

Much shorter times of stretching than those stated above will sufllce to increase the strengthening ofthe gels, particularly if tanning is speeded concurrently by the use of more potent tanning agents, so that tanning is substantially completed while the stretching and relaxing action takes, place For example, if a strong tannin! agent, such as, for example, a bathof several percent, say

.1 to 5% of formaldehyde or .5 to 10% of acetaldehyde'or of parabenzoq'uinone is used in acid,

neutral or alkaline solution,- then the direct may be attainedin a matter'of seconds, by stretching and relaxing as few as 20.to times at a very rapid rate, for example with a holder, or by passing over rollers given a short swing reciprocating motion by means of a vibrator. Preferably the filament or 'him so stretched is left intact and is not cut or severed so that no curling or similar appreciable permanent deformation takes place.

The increases in strength thus obtained are generally not so large as those described in the first example, but are generally quite observable, amounting to as much as 1 to 5%, and more.

Fundamentally, the invention comprises an in crease in strength effected by several times repeated stretching and relaxing while progressive tanning is taking place and without anyappreciable concurrent bending or curling.

As forpractical applications, I contemplate the protein gels described as such, as new and tile filaments or artificial fibers having a muchhigher resiliency and tensile strength than has heretofore been possible may be made and woven into fabric. Suitable compositions are prepared v according to the invention by exposing the protein compositions after they have been poured or extruded, and after the tanning agent used has been incorporated, but before they have attained their final hardness or rigidityto a rhythmical stretching and relaxing action. This is accoinplished easily by passing the material in the form of a sheet, filament or the like over rollers. belts, reels or the like, of which every other revolves at a lower and every other at a higher speed, so that a slack is formed between every other pair of rollers and a tension between every other pair. Obviously, the desired result is accomplished by any other means for alternately stretching and relaxing the material produced while this is being hardened by the action of the tanning-agent. In the manufacture of hectograph blankets the hectograph gel formed, for example, of a usual 'gelatin-glycerin-water-aldehyde composition may be made in the form of a continuous ribbon without contact with a backing. This gel'ribbon is stretched and relaxed while hardening takes place, due to the action ofthe tanning agent.

This treated gel is then securbd to a backing in a to. which the mass will not bond. The belt is oi such lengththat the composition is completely set to a gel at the end remote from the application of the composition. From this end oi the belt the gel itself is carried over a series of rollers in a festoonlike arrangement so that every other roller would revolve at a-high speed and every other roller at low speed. In-this manner they mass is stretched between every slow revolving roller and every fast revolving roller and relaxed between every fast revolving roller and slow revolving roller, o that a continuous stretching tanning agent which comprises and relaxing takes place. Uponcompletion of the treatment the band of hectograph mass is slit and cut to pieces of appropriate size and bonded to the backing material by suitable mean such as by any of the various bonding agents for bonding hectograph masses to backings.

The invention manifestly is capable of wide peated at a rate of several time per minute on a protein composition containing an organic tanning agent, which composition is still in the proc- 9. The method of producing a tanned protein composition having improved tensile strength which comprises incorporatingan organic tanning agent in a protein composition and alternately stretching and relaxing said composition at least about 20 times concurrently with the increase in melting point of said gel caused by said tanning agent, without causing any appreciable permanent deformation of said gel.

10. The method of producing a tanned, plasticized gelatin mass having improved tensile strength, which method comprises mixin together gelatin, water, a less volatileplasticizer, and an organic tanning agent to obtain a composition which will form a sol at an elevated temperature and a gel on cooling, pouring said composition at an elevated temperature in its sol state on a surface, allowing the sol to cool and set to a gel, removing the gel in the form of a sheet from the surface, and alternately 'stretching and relaxing said gel sheet at the rate of ess of undergoing tanning and capable of undergoing substantial further tanning.

I claim:

1. The'm'ethod of improving the physical characteristics of a protein mass which comprises alternately stretching and relaxing said mass at influence of a tanning agent.

3. The method of improving the physical characteristics of a protein gel containing an organic tanning agent which comprises alternately stretching and relaxing said gel at least about 20 times while said gel is undergoing tanning.

4. The method of improving the physical characteristics of a protein gel containing an organic alternately stretching and relaxing said composition through a substantial distance of extension at least about vibrator at least about 20 times while said gel is undergoing tanning.

7. The method of improving the physical characteristics of a protein gel containing an organic tanning agent having a liquid disperse phase reater than the solid dispersed-phase, whichmethod comprises alternately stretching and relaxing said gel at least about 20 times substantially before said gel has completely reacted with said tanning agent, substantially without causing any permanent deformation of said gel.

8. The method of improving the physical characteristics of a formed article of manufacture made from a protein composition which comprises alternately stretching and relaxing said than a mass of atanned protein composition of formed article at least about 20 times while sub- Jecting the protein of said article to the-action of an organic tanning agent'without causing any appreciable permanent deformation of said gel.

several times per minute to extent of at least about 10% elongation for several days.

11. The method of making a formed article of protein having improved physical characteristics which comprises incorporating an organic tanning agent in a protein composition, forming said composition into an article of manufacture, and alternately stretching and relaxing said ar-' ticle at least 20 times before said tanning has brought about final hardness.

12. The method of making a protein sheet having improved physical characteristics which comprises incorporating an organic tanning agent in a protein composition, forming said composition into a sheet, and alternately stretching and relaxing said sheet at least 20 times before said tanning agent has brought about final brought about final hardness, without causing any appreciable permanent deformation of said filament. I

15. A tanned protein composition in the form of an artificially shaped mass obtained by alternately stretching and relaxing said mass at least 20 times during tanning by means of a vibrator, said mass being characterized by having substantially greater elasticity andtensile strength filament at least about 20 times while said filamentis under the influence of a tanning agent.

.JOHAN moaxs'ran. 

